This invention relates to valves and more particularly to degassing valves for use in flexible packaging, packages including such valves and methods of making such valves.
Packages made out of flexible material are commonly used to store products to isolate the products from the ambient atmosphere. Those products may be agricultural products, foodstuffs, chemicals, etc. It is a common practice to include in various types of flexible packages a valve to enable air which may be trapped within the bag or gases produced by the contents of the bag to exit the bag through the valve while precluding the ambient atmosphere, e.g., air, from entering into the bag through the valve. Examples of such degassing valves are those sold by Pacific Bag, Inc., of Bellevue, Wash. SIG-Schweizerische Industrie-Besellschaft, of Heuhausen am Rheinfall, Switzerland, also sells such valves (e.g., the valve disclosed in U.S. Pat. No. 4,420,015). Wipf AG Verpackungen, of Volketswil, Switzerland, also sells such valves (e.g., the valve disclosed in U.S. Pat. No. 4,444,219). Luigi Goglio Milano, SPA, of Milan, Italy also sells such valves (e.g., the valve disclosed in U.S. Pat. No. 3,799,427, as well as other valves).
Other examples of one-way valves for packages are also found in the following: U.S. Pat. No. 3,595,467 (Goglio); U.S. Pat. No. 4,576,285 (Goglio); and U.S. Pat. No. 4,705,174 (Goglio).
While the aforementioned valves of the prior art are generally suitable for their intended purposes to vent entrapped gas or air from the flexible package, they still suffer from one or more disadvantages, e.g., complexity, difficulty in assembly, effectiveness in operation.
For example, the valves disclosed in the heretofore identified Goglio patents are somewhat complex in construction, i.e., they comprise three basic components, namely, a valve body, a flexible valve element, and a cap. The valve body includes a least one inlet aperture and a valve seat adjacent the aperture. The cap is a hollow, cup-shaped member which is fixedly secured to the valve body and when so attached forms a hollow interior for the valve. The cap includes an aperture in fluid communication with the interior of the valve to serve as an exit port of vent for the valve. The valve element is a flexible, disk-like member that is disposed within the hollow interior of the valve on the valve seat and normally covers the aperture. The cap member includes a downward projection for engaging a surface of the valve element to ostensibly hold the valve element in place on the valve seat over the aperture. A layer of silicone oil or some other viscous fluid is typically interposed between the valve element and the valve seat to facilitate operation of the valve.
As should be appreciated the Goglio valves require close tolerance parts and precise assembly to ensure effective and repeatable operation. Thus, if there is an inconsistency in the valve's assembly or in the components making up the valve, it may not operate properly. For example, it has been determined that if the projection from the valve cap does not appropriately engage the flexible valve member to hold the it in place on the valve seat, it may fail to reseat itself properly after opening (flexing). Such mis-operation is more prone to occur in applications wherein the valve is subjected to freezing temperatures and changes in ambient pressure, such as could occur if the valve is transported over a mountain range.
The heretofore identified valve sold by Pacific Bag, Inc. while basically comprises a two-piece assembly, is nevertheless a complicated assembly. In particular, it comprises a base portion in the form of a cap-like member having a rubber disk or valve member in it. The cap includes three arcuate gas exit slots which are disposed in a circular array in the center portion of the base member. A circular valve disk, such as made of neoprene or some other rubber, is disposed within the base member and over the three arcuate outlet ports. The valve is designed to flex to enable gas to flow around it and out through the exit ports when the pressure within the package exceeds the ambient pressure. The rubber disk member is held in place by three inwardly extending ears projecting inward from the base or cap member. The mounting arrangement of the disk, i.e., being held in place by the three inwardly extending ears, renders this valve susceptible to the disk popping out of place when gas vents out the valve. Such action thus renders the valve inoperative.
The heretofore identified SIG valve, is a somewhat complex valve that basically comprises a three-piece assembly, that is, a cup-shaped member having a central opening or port, a very thin flexible plastic disk or diaphragm, and an insert or clamping member of generally rectangular shape but having arcuate opposed ends arranged to be snap fit into the cap-shaped member to hold the flexible valve member between it and the outlet port. Gases are enabled to flow through the space between the linear sides of the clamping member and the arcuate portion of the cap under the polyester valve disk or diaphragm and out through the central opening when the pressure within the interior of the flexible package exceeds that of the ambient atmosphere.
The heretofore identified Wipf valve is also of relatively complex construction, e.g., it basically comprises a three-piece member, that is, a cup-shaped valve body having a plural holes or ports, a very thin flexible plastic disk or diaphragm, and an insert or keeper of generally I-shape fit in the cap-shaped member to hold the flexible diaphragm between it and the ports. Gases are enabled to flow through the space between the sides of keeper and the arcuate portion of the cap under the diaphragm and out through the plural ports when the pressure within the interior of the flexible package exceeds that of the ambient atmosphere.
Thus, a need presently exists for a valve which is simple in construction, can be made easily and inexpensively, and operates effectively and repeatedly under various conditions of service.